The Infallible Line is certainly not one of the most expensive makeup lines on the market but for the price, most of their products are well formulated, long lasting and long wearing. Most of the products I have tried from this particular line work quite well and normally I don't have any reactions to them.
The Infallible undercover stick has quickly become a favorite of mine simply because it stays put, particularly in very warm weather. The Infallible cover stick comes in a Fair, Light Fair, Medium and dark shade so matches practically any skin color.
The cover cream goes on smoothly using either your ring finger or a concealer brush, and doesn't leave a cakey finish which I really like. If you want to wear nothing else over or under the concealer, the formulation and longevity of the makeup allows this. The concealer stays put without any powder application necessary afterwards to set it. During a particularly warm day, usually other concealers I've tried have failed quickly but the Infallible 6 hr concealer stayed on nicely, didn't crease and continued to add a brightness to the eye area that looked natural and smooth.
Overall, the amount of concealer necessary to cover under eye circles is quite minimal and with careful application I believe this particular product will last for quite awhile. It's neither too oily nor too dry and so far I've not noticed any reason to stop using this.
I'm not certain whether it would be the ideal concealer for covering very dark circles but for my purpose, the application looks natural, goes on very effortlessly and quickly, light enough not to look made up but heavy enough to do the job it claims to do. At $8.97 per tube it's a reasonable value.